1. Field of the Invention
The present invention relates to incontinence monitoring and/or position monitoring of patients.
2. Description of Related Art
Incontinence is universal among the very young and increasingly common among the very old. Incontinence may also be a consequence of surgical procedures or neurological impairments. There is a need to determine when an absorbent product, e.g., a diaper or bed pad, for a patient who is incontinent is wet, without disturbing the patient.
A wide variety of means have been devised to detect when a diaper is wet without removing the diaper. These include visual indicators and electronic wetness detection systems. Visible indicators for disposable diapers typically are chemicals within the deep layers of the diaper, adjacent to a translucent moisture impermeable outer layer, that change color when wet. For a caregiver to see that the diaper is wet and needs to be changed, the indicator region of the diaper must be visible. This requires undressing the wearer of the diaper when the user is dressed, and pulling back blankets, sheets and bed clothes when the wearer is in bed. It also may require rolling a wearer over to view the rear of the diaper if the wearer is asleep on their back. The process of obtaining a view of chemical wetness indictors is clearly disruptive of the wearers activities. It may be particularly disruptive when checking for wetness awakes a sleeper whether or not their diaper is actually wet and in need of changing. The chief virtue of visible wetness indicators is that they are inexpensive to produce.
Various electronic diaper wetness detection indication systems have been developed specifically to provide remote sensing of when a diaper needs to be changed. These typically involve at least two components attached to the diaper. Systems dependent on radio transmitters also require a remote radio receiver. Electronic wetness detection systems usually have an inexpensive disposable sensor within the diaper and a reusable alarm or transmitter attached to the outside of the diaper that is connected to the wetness sensor within. Typically, the sensing element includes two or more conducting elements separated by a wetable membrane that insulates between the conductors when dry and conducts electricity or otherwise changes impedance between the sensor when wet with urine or other electrolyte solutions. The electrical power that activates the external signaling circuit may be sourced from a battery in the attached electronics package or by galvanic reaction between metallic electrodes in the diaper.
For audio alarms, the detachable reusable electronic package produces an audible signal to alert the caregiver when urine is sensed within the diaper. For radio frequency (RF) alerting systems, a radio transmission is made by the reusable external transmitter when urine is sensed within the diaper. This RF transmission is received by a remote device that is configured to alert a caregiver that the diaper is wet.
Audible electronic systems have the disadvantage of requiring the caregiver to be within hearing range at the time the audible alert is generated. Furthermore, sound generated can be disruptive of ongoing activities, such as sleep or social interaction, particularly for incontinent adults. Radio alerting systems can be more private in signaling the need to change a wet diaper or incontinence bed pad.
While the electronic systems described above have the advantage of not requiring a caregiver to physically disturb the wearer of the diaper in order to determine if the diaper is wet, the reusable electronics package attached to the diaper may be uncomfortably large and must be recovered after each diaper change for reattachment to a fresh diaper. The need to recover and reuse a relatively expensive electronics package attached to a soiled diaper every time the diaper is changed is onerous, especially when the diaper is soiled with feces. Experience shows that the detachable electronics packages are often misplaced or lost in institutional settings when diapers are removed because wearers are being bathed or changed or having a medical procedure.
One type of prior art electronic wetness sensor for incontinence products includes two or more sensing elements separated by an insulating region, attached to the electronic sensing circuit. Usually, these sense wetness by the increased conductance between two electrodes, but changing capacitance has also been used to detect wetness. A problem with these types of prior art incontinence detecting systems is that they require the attachment of a powered audible or radio-signaling device to the diaper and that they require sensing electrodes to function.
Another prior art electronic wetness sensor for incontinence products is disclosed in U.S. Pat. No. 5,570,082 to Mahgerefteh et al. This wetness sensor includes a circuit having two spaced sensing elements connected in series with an antenna and a nonlinear element, e.g., a semiconductor diode. In the absence of discharged urine, the circuit is not responsive to a magnetic excitation signal due to the lack of conduction between the two sensing elements. However, when discharged urine forms a conductive path between the two sensing elements, the circuit is enabled to respond to the magnetic excitation by imposing detectable harmonics thereon. A problem with this type of prior art incontinence detecting system is its lack of a response when discharged urine does not form a conducting path between the two sensing electrodes.
It is, therefore, an object of the present invention to overcome the above problems and others by providing a system and method of use thereof for remotely detecting when a diaper is wet or when it is not wet without the need to attach a powered signaling device to the diaper. It is an object of the present invention to provide a system and method of use thereof for remotely detecting the position of a patient. Still further objects will become apparent to those of ordinary skill in the art upon reading and understanding the following detailed description.
Accordingly, we have invented a patient fluid discharge monitoring system that includes a liquid absorbent material configured to be positioned to receive fluid discharged from at least one of urine discharge orifice and a fecal discharge orifice of a patient. A first RF tag is positioned in contact with or in spaced relation with the liquid absorbent material. The first RF tag is responsive to a wireless excitation signal in the absence of discharged fluid in the liquid absorbent material and responsive to the excitation signal in the presence of discharged fluid in the liquid absorbent material for causing at least one of (i) a unique change in the excitation signal and (ii) a change in a unique wireless response signal output by the first RF tag in response to the wireless excitation signal.
The system can include means for transmitting the excitation signal and means for detecting any change in the excitation signal and/or the response signal. The first RF tag can include an inductor coupled in parallel with a capacitive storage element, a magnetostrictive element biased in a magnetic field of a magnet, or an antenna coupled to an integrated circuit (RFID tag) that is responsive to the excitation signal received by the antenna for causing a unique change in the excitation signal or the response signal.
A dry electrolyte can be included in the liquid absorbent material and/or on the first RF tag. When discharged fluid combines with the dry electrolyte, the combination detunes the first RF tag from its resonant frequency and/or shields the first RF tag from the excitation signal.
The absorbent material can be received in a diaper having the absorbent material and the first RF tag received between an inner lining and an outer lining that is at least in part fluid permeable, or in a pad having the absorbent material and the first RF tag received in a casing that is at least in part fluid permeable.
The system can further include a transceiver for supplying the excitation signal to the first RF tag and for detecting the change in the excitation signal and/or the response signal. A detector can process the change detected by the transceiver and generate a signal as a function of the detected change.
A second RF tag can also be positioned in contact with or in spaced relation with the liquid absorbent material. The second RF tag is responsive to a wireless excitation signal in the absence of discharged fluid in the liquid absorbent material and responsive to the excitation signal in the presence of discharged fluid in the liquid absorbent material for causing at least one of (i) a unique change in the excitation signal and (ii) a change in a unique wireless response signal output by the second RF tag in response to the excitation signal.
The second RF tag can be spaced from the first RF tag whereupon discharged fluid received in the absorbent material first causes the first RF tag to respond and cause any change in the excitation signal and/or its response signal and then causes the second RF tag to respond and cause any change in the excitation signal and/or its response signal. The first and second RF tags can also be formed on a common flexible substrate. In order to distinguish the first RF tag from the second RF tag, the unique change in the excitation signal caused by the first RF tag is different than the unique change in the excitation signal caused by the second RF tag. In response to flexing of the substrate, the unique changes in the excitation signal caused by the first and second RF tags change together whereupon the difference between the changes in the excitation signal remain substantially the same.
We have also invented a patient fluid discharge monitoring system that includes an article configured to be worn next to the skin of a patient. The article includes an absorbent material for absorbing fluid discharged by the patient. An RF tag is positioned adjacent the absorbent material. The absorbent material and the RF tag are arranged whereupon in the absence of fluid in the absorbent material the RF tag has a first detected response to a wireless excitation signal and in the presence of fluid in the absorbent material the RF tag has a second detected response to the excitation signal. The second detected response can be a null.
The system further includes means for generating the excitation signal, means for detecting each response of the RF tag to the excitation signal and means for generating a signal as a function of at least one response of the RF tag.
A dry electrolyte can contact or cover at least part of the RF tag. In response to fluid combining with the dry electrolyte, the combination attenuates the excitation signal received by the RF tag and/or detunes a resonant frequency of the RF tag.
The article can be a diaper or a pad, such as an incontinence pad or bandage, having a cover or lining that is at least in part fluid permeable.
The system can include another RF tag positioned adjacent the absorbent material. The absorbent material and the other RF tag are arranged whereupon in the absence of fluid in the absorbent material the other RF tag has a first detected response to the excitation signal and in the presence of fluid in the absorbent material the other RF tags second detected response to the excitation signal. Alternatively, the other RF tag can be positioned in the article and isolated from the absorbent material whereupon the other RF tags one detected response to the excitation signal regardless of the presence or absence of discharged fluid in the absorbent material.
One RF tag can be positioned in the article to provide a first delay between the first and second detected responses thereof when the article receives discharged fluid in the form of urine and another RF tag positioned in the article to provide a second delay between the first and second detected responses thereof when the article receives discharged fluid in the form of moist fecal discharge, wherein the second delay is shorter than the first delay.
Lastly, we have invented a method of monitoring patient fluid discharge. The method includes providing at least one article configured to be worn by a patient. The article includes absorbent material and an RF tag received adjacent the absorbent material. The RF tag is excited with an excitation signal and the response of the RF tag to the excitation signal is detected. The detected response of the RF tag is compared to a reference response wherein the RF tag has a first detected response when the absorbent material has no fluid therein and a second detected response when the absorbent material has fluid therein. The second detected response can be a null.
The reference response and the first detected response can be substantially the same, however, the reference response and the second detected response are different. The method can further include generating an alarm in response to detecting the difference between the reference response and the second detected response.
The second detected response of the RF tag can include a lower amplitude than the first response and/or a different frequency than the first response.
A plurality of RF tags can be distributed throughout the article. The second detected response of each RF tag can occur in response to the absorbent material adjacent the RF tag having fluid therein. The RF tags can be arranged in the article whereupon fluid received in the absorbent material arrives adjacent each RF tag at a different time.